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MEL definition

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MEL definition

Old 23rd Jun 2018, 08:40
  #21 (permalink)  
 
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This is what EASA states in its document 'Certification Specificationsand Guidance Material for Master Minimum Equipment List CS-MMEL':
‘Commencement of flight’ is the point when an aircraft begins to move under its own power for the purpose of preparing for take-off.
[...]

Operators should include guidance in the MEL to deal with any failures which occur between the commencement of the flight and the start of the take-off.
So it is very, very, very clear till what stage a defect needs to be entered in the Tech Log, rectified by an engineer or possibly deferred under the MEL: the release of the parking brake for taxi.

You'd be surprised how many pilots don't grasp this simple fact
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Old 23rd Jun 2018, 09:31
  #22 (permalink)  
 
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Originally Posted by PENKO View Post
the release of the parking brake for taxi.
100% agree, my previous operator had exactly the same wording in our OM(A) and that cleared any possibile doubts amongst the pilot population. My current one uses the wording "commencement of the flight" which should still be pretty clear but does indeed create confusion sometimes over a widespread fleet. As we all know most of the times wording is kept in such a way that it can be twisted and interpreted as needed depending on whom is supposed to be right or wrong
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Old 23rd Jun 2018, 10:08
  #23 (permalink)  
 
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Same as PENKO.

From our FOM:

''The crew must refer to the MEL if a failure occurs or a component is degraded or a function is inoperative before taxi-out. If a failure occurs between the start of taxi ( when the aircraft begins to move under his own power) until the start of the takeoff roll it is subject to good pilot judgement and airmanship. The PIC may refer to the MEL to make an assessment before any decision to continue the flight is taken. This is particularly true for those failures that might affect the takeoff performance (i.e loss of spoilers, brake failure, etc.).''
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Old 23rd Jun 2018, 10:09
  #24 (permalink)  
 
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Originally Posted by PENKO View Post
Just to be clear, it's misleading in this discussion to say 'the MEL applies'.
The MEL does not 'apply' anything. What applies is that you go back to the gate, open the doors, enter the defect in the tech log, call an engineer, wait an hour for the engineer to arrive, and THEN, if the fault cannot be cleared in a reasonable time frame, possibly apply the MEL in order to dispatch.
Maybe where you are, WE are on the headset for departure at our airline!
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Old 23rd Jun 2018, 10:37
  #25 (permalink)  
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No it is not clear when to apply the MEL or the Abnormal checklist, but it used to be clear (up to approx 15 years ago).

The MEL should be applied up until setting takeoff power if you have failures on startup/taxi, and when airborne you look into the Abnormal checklist. That is the way we used to do it.

Let me give an example why : on taxi out you have an ECAM warning, and this failure is a “NO DISPATCH” according to the MEL. Common sense would be not to continue the flight, but as it is company procedure in many places, it is up to captain to decide if it is OK to continue (after using “good airmanship etc”.

In todays complex aircraft it should not be up to the captain to decide that. The MEL should be used/applied up to setting takeoff power.

Please give examples on in which European companies is the MEL used/applied that way (up to setting takeoff power) ?



Last edited by jaja; 23rd Jun 2018 at 10:58.
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Old 23rd Jun 2018, 11:08
  #26 (permalink)  
 
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Many MEL '' No dispatch'' are conservative and therefore not busine$$ friendly so it would not necessary make sense to return to the gate especially if you are in a remote area where they would not be able to fix the aircraft. Most of the time, it will have zero effect on the flight as there is redundancy. As long as you are aware of the potential consequences and comfortable with it. Then why not continue. I personally like the way it is.
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Old 23rd Jun 2018, 11:12
  #27 (permalink)  
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Yes Pineteam, that is also the answer I get from many, BUT if we have such good system redundancy why should we in the first place appy the MEL restrictions if we have failures before pushback ? It does not make sense !
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Old 23rd Jun 2018, 11:16
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Maybe since we are still att the gate, probably with no pax on board with engines shut down, and maintenance available it's worth it to try and fix it? During taxi we are left alone. xD
Just speculating. I'm not sure why. xD
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Old 23rd Jun 2018, 11:23
  #29 (permalink)  
 
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Originally Posted by jaja View Post
Yes Pineteam, that is also the answer I get from many, BUT if we have such good system redundancy why should we in the first place appy the MEL restrictions if we have failures before pushback ? It does not make sense !
The MEL provisions also consider the worst case scenario of a subsequent inflight failure of another critical system and therefore protects You accordingly. Once the applicability of the MEL ceases it is up to You to cater for all the different scenarios that could happen and decide. Regardless of what the MEL says the final word is anyway always with the flight crew (ie the Captain) if a more restrictive interpretation of the MEL is required given the conditions of the day.
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Old 23rd Jun 2018, 11:30
  #30 (permalink)  
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Originally Posted by sonicbum View Post
The MEL provisions also consider the worst case scenario of a subsequent inflight failure of another critical system and therefore protects You accordingly. Once the applicability of the MEL ceases it is up to You to cater for all the different scenarios that could happen and decide. Regardless of what the MEL says the final word is anyway always with the flight crew (ie the Captain) if a more restrictive interpretation of the MEL is required given the conditions of the day.
yes SONICBUM that is exactly why you should apply the MEL up until setting takeoff power = no normal captain or technician can fully understand the consequences of flying with a “NO DISPATCH” failure on todays complex aircraft.

So I ask again : are there examples on a European company who apply/uses the MEL up until setting takeoff power ?
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Old 23rd Jun 2018, 12:25
  #31 (permalink)  
 
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Originally Posted by jaja View Post
No it is not clear when to apply the MEL or the Abnormal checklist, but it used to be clear (up to approx 15 years ago).

The MEL should be applied up until setting takeoff power if you have failures on startup/taxi, and when airborne you look into the Abnormal checklist. That is the way we used to do it.

Let me give an example why : on taxi out you have an ECAM warning, and this failure is a “NO DISPATCH” according to the MEL. Common sense would be not to continue the flight, but as it is company procedure in many places, it is up to captain to decide if it is OK to continue (after using “good airmanship etc”.

In todays complex aircraft it should not be up to the captain to decide that. The MEL should be used/applied up to setting takeoff power.

Please give examples on in which European companies is the MEL used/applied that way (up to setting takeoff power) ?




If you ask me what is whise, then yes, of course, the MEL is one of the things you consider in your scenario of ECAM during taxi. The MEL is also a wonderful companion with ECAM in flight if time permits, or reading FCOM in bed at home.

If you ask what are the rules, then the rules are very clear, see my quote in an earlier post.
If you disagree with this, then please explain why. I pointed out that EASA also has the provision regarding failures during taxi. This should answer your initial question.

As for your point that we need tailored on ground procedures for dealing with failures, well, that's exactly what you have in your MEL: once dispatched but before TO, complete the QRH/ECAM and consider the implications of the MEL, maintenance facilities etc and then decide to go or not. But you are not bound by the MEL at that stage.

Last edited by PENKO; 23rd Jun 2018 at 12:40.
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Old 23rd Jun 2018, 13:18
  #32 (permalink)  
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yes PENKO, but the average flightcrew/technician can not “consider the implications of the MEL”

so if you as a flightcrew decide to continue the flight, after having a failure during taxi that is a “NO DISPATCH” according to the MEL, then indeed you are on “un known ground”.

Why not be professional, and consider the aircraft “not airworthy” if you have a “NO DISPATCH” fault during taxi ?
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Old 23rd Jun 2018, 13:33
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That's a different discussion jaja. An interesting discussion for those quiet cruise portions on a long flight indeed, but still a different discussion.
Now we can produce a long list of failures and ask 'would you take off'. Or we can ask one simple question: why have the regulators chosen the moment of taxi as the start of a flight with respect to defect handling? Apparently they trust our professionalism.

Fair enough, no?

Last edited by PENKO; 23rd Jun 2018 at 13:51.
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Old 23rd Jun 2018, 13:46
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Originally Posted by jaja View Post
Why not be professional, and consider the aircraft “not airworthy” if you have a “NO DISPATCH” fault during taxi ?
Because a return to the gate can be extremely expensive if for instance the flight is cancelled. Being safe is good but you can’t be overly safe and competitive at the same time. Airlines main target is to make profit. It’s a business. We should not forget that.
How many times have you heard of a serious incident/accident after a crew decided to continue a flight after a « no dispatch failure » during taxi? Must be extremely rare otherwise I would expect that we apply the MEL the way you describe.


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Old 23rd Jun 2018, 17:52
  #35 (permalink)  
 
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Originally Posted by Small cog View Post
How can you apply requirements and restrictions of the MEL when (M) is required, without returning to the gate?
Well You can't that's why You need to balance risks, assess the situation and come up with a decision using all the available tools. If possible a phone/satcom/HF call to your maintenance team while at the holding point could give you valuable inputs to come up with your decision and if you're still stuck a call to your duty pilot (if there is one where your work) can help you out as he is going to speak on behalf of the company even though he's not going to decide for you but most likely give you "food for thoughts". Main thing when in a grey area is to get as many inputs as possible before jumping to a decision and being told "oh yeah but you could have talked to etc..". In the end no one decides for You but if the feeling You get from all around is that it smells "dodgy" then the parking bay is where you are heading to.
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Old 23rd Jun 2018, 18:57
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Clear I would hope...
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Old 23rd Jun 2018, 19:27
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This is not EASA-based.
So to be clear, you would go back to the gate for say..a burnt turn off light?
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Old 23rd Jun 2018, 20:43
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Originally Posted by Small cog View Post


Nice idea, but I would suggest it would be a brave manager or engineer who would authorise departing without a tech log entry. If you having enough doubt to call them ...

Ever been told “it’s OK” and then asked of it in writing? I did once, and I got it (I didn’t agree with CP and engineering that I should do an engine run after a problem). Carried out the requested engine run ... very expensive bang followed. Play safe.

Just my 2 cents worth.
Why so paranoid? It's perfectly legal, no tech log entry necessary after you've dispatched. Any professional engineer will have no hesitation to advise you to go or not go, in writing, or on a recorded phone conversation.

I'm glad I work with sensible professionals who are not afraid to offer sensible advise or take sensible decisions. Also in writing when requested.
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Old 23rd Jun 2018, 21:44
  #39 (permalink)  

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The regulation is worded the way it is for a reason. By people who - unlike common line folks such as us here (both FD an MX) - actually do know the backgroud, understand the implications, and are expertly trained in writing legal documents.

jaja, have you considered if perhaps the strong discord between your convictions and the law could be due to lack of education on the side of the liveware unit? There are valid answers to your queries, yet until you pass through that door they could remain out of sight.

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Old 13th Jul 2018, 18:45
  #40 (permalink)  
 
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Boeing 767 DDG quotation "Upon completion of any applicable procedures and prior to takeoff, the operator’s MEL should be consulted to determine if relief is available for continued operation with system faults displayed at the alert level (Warning, Caution, Advisory).", so Boeing's policy is: if after or during engine start and before TO there is an alert message: 1) do the respective non-normal checklist (NNC), 2) check the DDG or MEL to make decision. For me, it is still unclear what to do if on this stage and before ETOPS entry point there some issues related to ETOPS MEL ITEMS and which usually not considered for NON-ETOPS flights.
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